In an internal combustion engine of an automobile or the like, there have been widely used a direct injection high-pressure fuel pump which injects fuel directly into a combustion chamber and has a flow-rate control valve for increasing the pressure of the fuel and discharging a desired fuel flow rate.
Generally, as the pressure supplied to a fuel injector is larger, the fuel spray injected from the fuel injector is more atomized, and the combustion efficiency is improved. Thus, high discharge pressure is required as the performance of a high-pressure fuel pump. Furthermore, in order to control the flow rate under the condition of high engine speed, it is necessary to open and close the flow-rate control valve within a predetermined time, and improvement in the responsiveness of the flow-rate control valve is required.
PTL 1 discloses a method as a driving portion structure for improving the responsiveness of the flow-rate control valve. PTL 1 discloses a method for increasing the magnetic attraction force and improving the responsiveness by setting the saturation magnetic flux density of the stainless steel forming a fixed core and a movable core larger than the saturation magnetic flux density of the stainless steel forming a case.